Background: Umbilical cord blood gas values are better indicators of perinatal asphyxia than Apgar scores. However, the reported normal range of umbilical blood gas values vary greatly in the literature. The aim of this prospective study was to establish the normal range of umbilical cord blood gas values in our labour ward.
Methods and results: Umbilical cord blood gas from 153 vaginal deliveries and 52 Caesarean sections for indication other than fetal distress were evaluated. In our labour ward, the mean and standard deviation of umbilical artery pH were 7.21 and 0.08 for vaginal deliveries and 7.22 and 0.07 for Caesarean sections respectively. The mean and standard deviation for umbilical artery base deficit were 5.08 and 3.85 for vaginal deliveries and 4.09 and 3.07 for Caesarean sections respectively.
Conclusion: In conclusion, pH of 7.05 is the statistical lower limit of umbilical artery pH in our labour ward and is a good cut-off value to indicate perinatal asphyxia. Five cases with abnormal umbilical artery pH (< 7.05) were also analysed and discussed.